Step 1

Place raisins and currants in a medium bowl; add 1 1/2 cups hot water. Cover and let soak overnight. Drain, reserving 1/2 cup soaking liquid.

Step 2

Pour 1 cup warm water (105°1-15°) into a small bowl. Sprinkle yeast over; let stand until dissolved, about 10 minutes. Place 2 3/4 cups flour and 2 Tbsp. butter in the bowl of a stand mixer with a dough hook attached. Mix on medium speed until butter is blended, about 2 minutes. Add yeast mixture and reserved soaking liquid from raisins and currants; beat on low speed for 4 minutes. Add raisins, currants, and salt; mix for 5 minutes.

Step 3

Transfer dough to a floured work surface (dough will be very soft). Form into a ball, adding just enough flour (about 2-4 Tbsp.) to prevent dough from sticking to your hands. Transfer to a bowl; dust top with additional flour, cover with a kitchen towel, and refrigerate for 1 hour.

Step 4

Transfer dough to work surface; shape into a ball. Return to bowl, sprinkle with flour, and let rise in a warm, draft-free area until doubled in size, about 3 hours.

Step 5

Butter two 8x4x2" metal loaf pans. Transfer dough to work surface. Divide dough in half. Form each half into a loaf shape and place in a prepared pan. Dust dough with flour, cover with kitchen towels, and let rise until dough reaches tops of pans, about 2 hours.

Step 6

Place one rack on bottom shelf of oven and another on middle shelf; preheat to 400°. Add water to an 8x8x2" metal pan to a depth of 1"; place on bottom rack. Bake bread on middle rack for 40 minutes. Carefully remove pan with water. Remove bread from pans. Lay loaves on sides on a baking sheet; bake 5 minutes. Turn loaves onto other side; bake 5 minutes. Turn right side up and bake until done, about 5 minutes. Let cool completely on a wire rack.